1. Field of the Invention
The present invention relates to a power controllable wireless communication device. In particular, the present invention relates to a wireless communication device for millimeter wave radar.
2. Description of the Related Art
Since the wireless communication device for millimeter wave radar is expensive at the present time, the wireless communication device for millimeter wave radar is applied to only some luxury cars. Development of an inexpensive wireless communication device for millimeter wave radar (MMIC: Monolithic Microwave Integrated Circuit) is demanded to popularize the millimeter wave radar up to the popular car.
On the other hand, in radio laws in countries, the range of allowable output electric power of millimeter wave radar is stipulated. Among the ranges of the allowable output electric power, minimum output electric power is stipulated by a radio law in Japan. That is, according to the radio raw in Japan, it is demanded to cause the minimum output electric power to fall in a width of 4.77 dB from maximum output electric power.
An electric power adjustment technique is used in the device for millimeter wave radar to satisfy the stipulation of the output electric power range in the radio law. However, the electric power adjustment technique becomes a cause of rising cost. If price lowering of the electric power adjustment technique can be implemented, it becomes possible to provide an inexpensive device for millimeter wave radar.
Techniques concerning the electric power adjustment of the millimeter wave radar are described in, for example, JP-4429347-B2 and JP-4087803-B2.